Merge tag 'write-page-prefaulting' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull iomap fixlet from Andreas Gruenbacher:
 "Fix buffered write page prefaulting.

  I forgot to send it the previous merge window. I've only improved the
  patch description since"

* tag 'write-page-prefaulting' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  fs/iomap: Fix buffered write page prefaulting

Author: torvalds

fs/iomap/buffered-io.c

@@ -765,7 +765,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 		 * same page as we're writing to, without it being marked
 		 * up-to-date.
 		 */
-		if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
+		if (unlikely(fault_in_iov_iter_readable(i, bytes) == bytes)) {
 			status = -EFAULT;
 			break;
 		}

mm/filemap.c

@@ -3779,7 +3779,7 @@ ssize_t generic_perform_write(struct file *file,
 		 * same page as we're writing to, without it being marked
 		 * up-to-date.
 		 */
-		if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
+		if (unlikely(fault_in_iov_iter_readable(i, bytes) == bytes)) {
 			status = -EFAULT;
 			break;
 		}